VersionTracker

How do I get the size of my files and folders (equivalent to TreeSize in XP):

Maybe it's your timing, and not the pressure at all. Keep in mind that the shift key needs to be held during the typing of the following character. The older mechanical action on a typewriter would give you instant feedback that the key was not held down completely. A computer keyboard, even one with mechanical switches, would not provide that same physical/optical feedback....

Try Graphic Converter (from versiontracker.com, etc). I know it offers to write a proressive JPEG, so it might read one. And save as a straight JPEG.

I've never had to do it myself (I keep my music backed up on DVD-Roms) but I've heard Senuti is good for retrieving songs back off your iPod: http://www.versiontracker.com/dyn/moreinfo/macosx/23390

Download WhatSize. It will show all your files and their size.

I have head about successful results using the Force Empty Trash AppleScript. Your milage may vary.

I think something like SharePoints might help.

I tried it but it only limits application usage, not folders.

Mac Minder at versiontracker.com

Looks like Mac Minder is the way to go: http://www.versiontracker.com/dyn/moreinfo/macosx/15893 Gives you full control and monitoring capabilities for each user account.